Conventionally, a technique for detecting the air pressure of a vehicle tire, and informing the user of the detected air pressure as a tire air pressure state is known.
As such technique, for example, Japanese translation of PCT publication No. 10-508264 discloses a technique that corrects an air pressure signal of a tire detected by a pressure sensor in association with a standard temperature (20°), and displays the corrected air pressure signal on a display of a vehicle.
However, in the above prior art, the tire air pressure state cannot be displayed unless a vehicle comprises a control unit for displaying the tire air pressure state, and a display, and there is room for improvement in display versatility.
That is, even in a vehicle which does not comprise a control unit for displaying the tire air pressure state and a display, when its tires has been changed to those with air pressure sensors, since the air pressure state of the changed tires is detectable, it is demanded to present the air pressure information of the changed tires to the user somehow in that vehicle.
Even when a vehicle comprises a control unit for displaying the tire air pressure state, if a display controlled by that control unit is a simple warning lamp, the tire air pressure state cannot be displayed by means of detailed numerical values. Hence, it is demanded to provide that air pressure state to the user somehow.